1. Field of the Invention
The present teaching is directed to methods of measuring an analyte in solution with a polynucleotide and a binding molecule, wherein the methods use competitive interference and recuperation of enzyme activity.
2. Description of the State-of-the-Art
The quantitative and qualitative measurement of analytes in a sample are used on a regular basis in chemistry and medicine. Immunoassays, for example, are typically binding assays used in detecting analytes that can include, for example, viral and bacterial antigens, immunoglobulins, hormones, cells, pharmaceuticals, toxins, and controlled drug substances. Since these techniques often lack in a desired amount of sensitivity and precision, amplification systems have been developed.
Many different immunoassays for qualitative and quantitative detections of analytes in a sample have been developed, such as enzyme-linked immunosorbent assay (ELISA), radioimmunoassay (RIA), and enzyme immunoassay (EIA). Immunoassays, for example, can be configured as heterogenous or homogenous assays, where a heterogenous assay is a two phase assay having solid and liquid phases, and a homogenous assay operates as a single phase. Heterogenous phase assays, such as ELISA, are commonly used, but they unfortunately require more steps than homogenous assays. Moreover, in addition to requiring the additional washing steps, the heterogeneous assays suffer in that they can never truly be automated. There are existing homogeneous phase assays, such as Enzyme Fragment Complementation (EFC), for example. EFC is a homogeneous assay based on antibody-antigen binding but, unfortunately, it has a poor sensitivity and resolution, in that it typically works for small antigens only, and only in assays having a high background activity.
A problem is that the currently available assays all require a skilled technician, only a few of the techniques have been successfully adapted for measurements of select analytes, and none of the techniques are homogenous and sensitive to a variety of analytes and under a variety of assay conditions. Accordingly, one of skill will appreciate a homogenous assay that is easy to use, takes less time than heterogeneous assays, has a high sensitivity and precision, and is capable of automation.